Generation and characterization of a complete null estrogen receptor alpha mouse using Cre/LoxP technology.
Conventional estrogen receptor alpha knockout (neo-ERalphaKO, neo-ERalpha(-/-)) mice contain a truncated and chimeric ERalpha fusion protein that retains 35% estrogen-dependent transactivation activity, and therefore the in vivo ERalpha function is difficult to study thoroughly. Furthermore, these neo-ERalpha(-/-) mice cannot be used for tissue and temporal specific ERalpha deletion. Therefore, there is a clear need to establish a floxed ERalpha mouse line that can knockout ERalpha specifically and completely in each selected cell type. Here we generated floxed ERalpha mice using a self-excising ACN (tACE-Cre/Neo) cassette. Mating the floxed ERalpha mice with ACTB-Cre mice produces a deletion of the floxed allele disrupting the reading frame of the ERalpha transcript so that no ERalpha protein is detected in the ACTB-Cre/ERalpha(-/-) mice. Expression of ERalpha target genes, such as G-6-PD and lactoferrin, is diminished by over 90% in the ACTB-Cre/ERalpha(-/-) uterus, but not in the neo-ERalpha(-/-) uterus. Furthermore, we also validated that ACTB-Cre/ERalpha(-/-) females have a hypoplastic internal genital tract, polycystic ovaries with hemorrhagic follicles, infertility, and higher body weight. Together, our data clearly demonstrate that the newly established floxed ERalpha mouse is a reliable mouse model for future studies of ERalpha roles in vivo in the selective estrogen target tissues. The complete knockout of ERalpha in the ACTB-Cre/ERalpha(-/-) mice will also provide an improved mouse model to study the role of ERalpha in vivo.
Chen
Ming
M
George Whipple Lab for Cancer Research, Departments of Pathology and Urology, University of Rochester Medical Center, Rochester, NY 14642, USA.
Wolfe
Andrew
A
Wang
Xi
X
Chang
Chawnshang
C
Yeh
Shuyuan
S
Radovick
Sally
S
D000818:Animals; D001835:Body Weight; D047628:Estrogen Receptor alpha / Q000235:genetics / Q000378:metabolism; D005260:Female; D005298:Fertility / Q000502:physiology; D055785:Gene Knockdown Techniques; D007246:Infertility; D019426:Integrases / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D023421:Models, Animal; D014599:Uterus / Q000002:abnormalities / Q000033:anatomy & histology / Q000378:metabolism
D047628:Estrogen Receptor alpha; C045073:Cre recombinase; D019426:Integrases